Conventionally, some techniques have been discussed for obtaining and grasping biological information, typically health condition of a living body, by measuring and analyzing biological gas components released from the living body. For example, Patent Document 1 and Patent Document 2 disclose techniques for detecting diabetes and measuring the degree of combustion of body fat by detecting a concentration of acetone included in an expiration gas. Also, Patent Document 3 discloses a technique for detecting abnormal proliferation of intestinal anaerobic bacteria and malabsorption syndrome by sensing hydrogen included in an expiration gas. Also, Patent Document 4 and Patent Document 5 disclose techniques for implementing complicated medical examination by detecting several types of gas components in an expiration gas by means of multiple types of gas detection elements for acetone, nitric monoxide, carbon dioxide, hydrogen and ammonia as well as detecting a single gas component in the expiration gas.
Many types of gas components coexist at various concentrations in a biological gas such as the expiration gas. In a case where a specific gas component is measured (detected and/or concentration is calculated) without separating these gas components, there is a problem in that they interfere with each other and the desired gas component cannot be measured correctly. For this problem, a gas chromatography method is widely known for measuring each gas component by separating them. However, in general, the apparatus is large, and the operation method requires proficiency. Thus, the chromatography method is not appropriate for simple use.
Also, for this problem, techniques are known for selecting and using gas sensors that react selectively and specifically for respective biological gas components (patent documents 1, 3, 4 and 5, for example). However, it is practically difficult to find a sensor with which other gas components do not interfere at all, and, in the case where such selective and specific gas sensors are used, there is a possibility in that measured concentration becomes inaccurate when the concentration of the interference gas component is high. Further, since there are many types of biological gas components, in the biological gas, which can be used for health diagnosis and disease determination, it is difficult and impractical to prepare as many gas sensors, that specifically react particular biological gas components, as the types of biological gas components (Patent Document 6, for example).